Summary

Quantum computing could enable exponential speedups for certain classes of problems by exploiting superposition and entanglement in the manipulation of quantum bits (qubits). The leading quantum systems that can be used include trapped ions, superconducting qubits, and spins in semiconductors. The latter are considered particularly promising for scaling to very large numbers of qubits. On page 439 of this issue, Zajac et al. (1) demonstrate a quantum operation involving two qubits in silicon (Si), which is a major step for the field of semiconductor qubits. Together with easier-to-achieve manipulation of single qubits, these operations represent the basic steps of any quantum algorithm.